1. Field of the Invention
This invention relates to means for retaining the barrels in a rotating battery gun, e.g. a Gatling type gun.
2. Prior Art
The use of clamps to retain each of the barrels of a Gatling type gun in a predetermined mutual relationship is conventional, and typified by the center barrel clamp assemblies and the muzzle clamp assemblies used on the M61 20 mm automatic guns, as shown in T.O. 11W1-12-4-34 of Apr. 15, 1965, pp. 2-8 and 2-9. In these systems, all six gun barrels are initially secured to the rotor against longitudinal movement by respective interrupted threads, and subsequently the clamp assemblies are slid onto the barrels as a group. These assemblies serve mainly to limit centrifugal whipping of the barrels. These assemblies are fixed against longitudinal movement to every other barrel by means of two bolted together plates straddling an integral ring on the respective barrel. A similar muzzle clamp is shown by D. R. Helble in U.S. Pat. No. 2,898,811 issued Aug. 11, 1959. Other clamps are shown by H. Otto in U.S. Pat. No. 2,849,921 issued Sept. 2, 1958 and U.S. Pat. No. 2,872,847 issued Feb. 10, 1959; by F. Blodgett, Jr. et al in U.S. Pat. No. 4,015,508 issued Apr. 5, 1977; D. Perrin et al in U.S. Pat. No. 3,897,714 issued Aug. 5, 1975; and R. E. Prince et al in Ser. No. 791,753, filed Apr. 28, 1977.
Conventionally, the gun is supported both at its housing by recoil adapters, and at a barrel clamp assembly by an antifriction bearing which permits rotation and limited reciprocation of the barrel cluster. Each barrel, in turn, as it fires, is eccentric to the longitudinal axis of the gun, which develops a turning moment, about the center of gravity of the gun, through the supports. This results in longitudinal distortion of each of the barrels. Further, the cluster of barrels is free to rotate within the clamp and to twist about the longitudinal axis of the gun, also resulting in a longitudinal distortion. These distortions result in an increase in the dispersion of the trajectories of the fired projectiles from the at-rest-bore-sight of the gun. Additionally, in reaction to the rotational forces about the individual barrel longitudinal axis developed by the projectile as it is fired through the length of the barrel, the barrel tends to unthread itself from the rotor.